We plan to carry out experiments at the molecular level to understand how regulatorty mechansms of gene expression control the synthesis of a cytoplasmic and secretory (invertase) enzyme encoded by a single gene. This project will involve: (i) Cloning of invertase cDNA sequences. (ii) Cloning and structural analysis of the genome coup of SUC2 using the cDNA probe. (iii) Isolating mutations in the regulatory regions of the SUC gene. (iv) Alteration of cloned SUC gene regulatory regions in systems outside of yeast.